I have done the following, and it still prints only 1 side of the page.

File > Print > Options > under the duplex heading clicked the checkboxes
'front of the sheet' and 'back of the sheet'.  

I have a co-worker who can print on both sides using the same printer.  
However, she must be on a different version of word since she sets it up
under the Page Layout tab which provides her with different options.  I do
not have options in this tab to print to both sides.